Generally, as the demand for high speed multimedia data services rise, many efforts have been made to the technological developments to improve signal quality and spectrum efficiency for the purpose of providing the high speed multimedia data services on mobile radio communication channels.
In a radio communication system, multi-antennas are used to provide transmission diversity. An information capacity in the radio communication system can be considerably increased if the multiple transceiving antennas are used. If the multiple transceiving antennas are used together with a coding scheme, it is able to increase a transceived information capacity more effectively.
In this case, the coding scheme is called a spatiotemporal coding scheme. In the spatiotemporal coding scheme, in order for a receiving terminal to provide a full diversity effect and a coding gain without sacrificing a bandwidth, temporal and spatial correlations with signals transmitted from other antennas are configured with codes. There is STBC (space time block code) scheme as one of the spatiotemporal coding scheme.
FIG. 1A and FIG. 1B are exemplary block diagrams of a transmitting terminal structure and a receiving terminal structure, respectively.
Referring to FIG. 1A and FIG. 1B, a bit interleaved coded orthogonal frequency division multiplexing system using STBC (space time block code) includes a transmitting terminal 10 and a receiving terminal 100.
Referring to FIG. 1A, the transmitting terminal 10 includes a channel encoder 11, a bit interleaver 12, a serial/parallel converter 13, a mapping module 14 having at least two mappers 14a, an STBC encoder 15, and an inverse discrete Fourier transform (IDFT) module 16 having at least two inverse discrete Fourier transformers 16a. 
The channel encoder 11 attaches redundant bits to data bits to detect or correct an error that may be generated when transmitting via a channel.
To reduce a burst error and an effect of fading, the bit interleaver 12 mixes and disperses the coded bits by a prescribed bit unit so as to independently arrange the coded bits.
The serial/parallel converter 13 converts a it signal from serial sequence to parallel sequence.
Each of the mappers 14a included in the mapping module 14 transforms a bit signal inputted thereto into a corresponding symbol signal in correspondence to a prescribed mapping rule.
The STBC encoder 15 encodes the symbol signal using a block code for multi-antennas to obtain transmission diversity in time and space.
Each of the IDFTs 16a included in the IDFT module 16 modulates the symbol signal into an OFDM symbol, that is, transforms the symbol signal on a frequency domain into a signal on a time domain, and then transmits the transformed signal. If the IDFT 16a is replaced by an inverse fast Fourier transformer (IFFT), a quantity of calculation is reduced for more efficient implementation.
Referring to FIG. 1B, the receiving terminal 20 includes a discrete Fourier transform (DFT) module 106 having at least two discrete Fourier transformers 106a, an STBC decoder 105, a demapping module 104 having at least two demappers 104a, a parallel/serial converter 103, a bit deinterleaver 102, and a channel decoder 101.
Each of the discrete Fourier transformers 106a included in the discrete Fourier transform module 106 performs Fourier transform on the received OFDM symbol. If the symbol is modulated by the inverse fast Fourier transformer, the discrete Fourier transformer 106a can be replaced by a fast Fourier transformer.
The STBC decoder 105 and the demapper 104a transform the symbol signal transmitted via the multi-antennas into a bit signal.
The parallel/serial converter 103 converts the bit signal from parallel sequence to serial sequence in a manner reverse to that of the serial/parallel converter 13.
The bit deinterleaver 102 changes an order of the bit signal of serial sequence mixed by the interleaver 12 into the original order prior to the mixing.
And, the channel decoder 101 decides estimated data bits.